ISTANBUL (Reuters) - Suspected Kurdish militants fired rockets at the airport in Turkey’s main southeastern city of Diyarbakir on Saturday, sending passengers and staff scrambling for shelter, Dogan news agency said, but there were no immediate reports of casualties.

Four rockets were fired at a police checkpoint outside the VIP lounge, and passengers and staff were taken inside the terminal building for safety, the private news agency said. The attack happened not long before midnight (5.00 p.m. ET) on Saturday.

Broadcaster NTV said the rockets landed on wasteland nearby. There were no casualties and no disruption to flights, Diyarbakir governor Huseyin Aksoy told the news channel.

There was no immediate claim of responsibility.

Diyarbakir is the main city in Turkey’s largely Kurdish southeast, where Kurdish militants have waged a three-decade insurgency. The attack comes days after Turkey launched a military incursion into Syria aimed at driving back Islamic State and preventing territorial gains by Kurdish fighters.

Rebels supported by Turkey fought Kurdish-backed forces in northern Syria on Saturday, and Ankara said it had launched air strikes against both Kurdish militia fighters and Islamic State.

Turkey fears Kurdish militia fighters will fill the void as Islamic State is pushed back. It wants to stop Kurdish forces gaining control of a continuous stretch of Syrian territory on its frontier, which it fears could deepen the insurgency by Kurdistan Workers Party (PKK) militants on its own soil.

Diyarbakir airport largely handles domestic flights and is served by carriers including Turkish Airlines.

The PKK, which first took up arms against the Turkish state in 1984, is considered a terrorist organization by Ankara, the United States and the European Union. A ceasefire collapsed just over a year ago, and violence has since surged.